1. Field of the Invention
The present invention relates to an image sensing, and more particularly, to a color filtering and methods of manufacturing the same.
2. Description of the Related Art
Image sensors are devices that can transform optical information to electrical signals, and can include charge coupled device (CCD) image sensors and CMOS image sensors, among others. A CMOS image sensor can have advantages in terms of simplicity of operation, miniaturization and manufacturing cost reduction, which can be possible due to the integration of signal processing circuits and low power consumption. A CMOS sensor can sequentially output data by switching operations of MOS transistors disposed in each pixel in a pixel array.
A CMOS image sensor can include an optical sensor unit that can generate optical charge by sensing external light. A CMOS image sensor can also include a color filter array arranged on the optical sensor unit. FIG. 1 is a cross-sectional view of a conventional CMOS image sensor. Referring to FIG. 1, a plurality of photo diode regions 110R, 110G, and 110B can be formed on a semiconductor substrate 100, and light shielding layers 120 can be formed on the semiconductor substrate 100 between the photo diode regions 110R, 110G, and 110B so that the photo diode regions 110R, 110G, and 110B can be exposed. A plurality of color filters 140R, 140G, and 140B can be arranged on the semiconductor substrate 100 corresponding to the photo diode regions 110R, 110G, and 110B. Micro lenses 150R, 150G, and 150B can be arranged on the semiconductor substrate 100 corresponding to the color filters 140R, 140G, and 140B. An interlayer insulating film 130 can be interposed between the light shielding layer 120, the color filters 140R, 140G, and 140B, and the micro lenses 150R, 150G, and 150B.
In a conventional image sensor, the color filter can be an organic color filter, and can be formed by mixing dye or pigment in a negative photoresist. The organic color filter can include non-uniform particle sizes, and accordingly, transmittance of pixels may not be uniform, thereby resulting in defects such as black spots. Also, it can be difficult to form a pattern having a small pitch, and, as illustrated in FIG. 2, which shows optical transmittance of the conventional CMOS image sensor, there can be a greater possibility of color crosstalk.